This invention relates to a valve apparatus for use with a down hole tool. More specifically, but not by way of limitation, this invention relates to an apparatus used to circulate, position and/or orient a down hole tool in a wellbore.
Operators find it necessary to drill wells that are deviated or horizontal in inclination. One technique of drilling deviated or horizontal wells is to place a down hole tool, such as a whipstock assembly, in a well and mill a window from an inclined surface on the whipstock. With this process, the driller will include a measurement while drilling tool in the work string, with the measurement while drilling tool having a suite of sensors which may include azimuth, resistivity, conductivity, etc.
As readily understood by those of ordinary skill in the art, the MWD tool requires circulation of the drilling fluid within the string in order to communicate via the use of pressure pulses. Hence, the orientation of the whipstock can be determined. After determining the position and orientation, the anchor means, which is part of the whipstock assembly, can be hydraulically set within the wellbore. Thereafter, a window in the casing can be milled by a cutter and then the cutter can drill a bore hole into a target formation.